Apparatus and methods for biomimetic expression of breast milk

ABSTRACT

An apparatus for biomimetic expression of breast milk can comprise a breast interface having an expandable membrane configured to mimic the geometry of an infant&#39;s mouth. Various regions of the expandable membrane may be configured to simulate the structure and/or function of various parts of an infant&#39;s mouth. The expandable membrane may comprise one or more of a distal sealing region configured to simulate the lips, a superior region configured to simulate the hard palate, an inferior protruding region configured to simulate the gums, an intermediate curved region configured to simulate the tongue, and one or more internal expansion regions configured to simulate the soft palate and the throat. The expandable membrane may have a varying thickness throughout the one or more various regions to enable movement of the regions similar to the movement of the corresponding regions of an infant&#39;s mouth during nursing.

CROSS-REFERENCE

The present application is a continuation of U.S. patent applicationSer. No. 15/581,790, filed Apr. 28, 2017, and is a non-provisional of,and claims the benefit of, U.S. Provisional Patent Application62/329,382, filed on Apr. 29, 2016, the entire contents of which areincorporated herein by reference.

This application is related to the following provisional andnon-provisional patent applications: U.S. patent application Ser. No.14/221,113, filed on Mar. 20, 2014, now U.S. Pat. No. 9,616,156, U.S.patent application Ser. No. 14/616,557, filed on Feb. 6, 2015, U.S.patent application Ser. No. 14/793,606, filed on Jul. 7, 2015, U.S.patent application Ser. No. 14/793,613, filed on Jul. 7, 2015, U.S.patent application Ser. No. 14/793,617, filed on Jul. 7, 2015, U.S.patent application Ser. No. 14/858,924, filed on Sep. 18, 2015, now U.S.Pat. No. 9,623,160, U.S. patent application Ser. No. 15/094,690, filedon Apr. 8, 2016, U.S. patent application Ser. No. 15/094,704, filed onApr. 8, 2016, and U.S. patent application Ser. No. 15/349,917, filed onNov. 11, 2016, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention generally relates to medical and pediatricnutrition devices and methods, and more particularly relates to devicesand methods for expression and collection of human breast milk.

Breast pumps are commonly used to collect breast milk in order to allowmothers to continue breastfeeding while apart from their children.Breast pumps typically function by applying a vacuum at the breast topull on the nipple and the surround tissue while the nipple isconstrained within a substantially cylindrical chamber. The nipple canbe stretched within the cylinder and the combination of the stretchingand the negative pressure within the chamber can result in milkexpression.

When a nursing infant expresses milk from the mother's breast, theinfant's mouth generally creates a latching suction that pulls thenipple and the surrounding tissue into the mouth. The infant then uses acombination of cyclic vacuum and tongue movements to affect milkmovement within the milk ducts of the breast,

It would be desirable to provide apparatuses and methods for breast milkexpression that simulate the mechanics of how a nursing infant expressesmilk from the breast. Such biomimetic expression of breast milk mayimprove the efficiency of milk expression and increase the comfort ofthe user during the expression of breast milk.

At least some of these objectives will be satisfied by the devices andmethods disclosed below.

SUMMARY OF THE INVENTION

Systems, apparatuses, and methods are disclosed herein for biomimeticexpression of breast milk that simulate the mechanics of a nursinginfant's mouth during nursing.

In one aspect, an apparatus for biomimetic expression of breast milkfrom a breast comprises a rigid housing and an expandable membranecoupled to the housing to form a chamber therebetween. The expandablemembrane has a distal opening to receive at least a portion the breasttherethrough and a proximal opening opposite the distal opening. Theexpandable membrane is operably coupled to an actuatable assemblyconfigured to alternate between an actuation phase and a resting phaseduring operation. The expandable membrane comprises an expandable regionadjacent the proximal opening, the expandable region configured toexpand and move towards the rigid housing during the actuation phase ofthe actuatable assembly, thereby generating negative pressure at thebreast to cause the expression of breast milk from the breast. Theexpandable membrane further comprises a distal sealing region adjacentthe distal opening, the distal sealing region configured to fluidly sealagainst the breast. The expandable membrane further comprises at leastone movable region disposed between the expandable region and the distalsealing region, the at least one movable region configured to movetowards the breast during the resting phase to compress the breast.

A thickness of the expandable membrane may vary through differentregions of the expandable membrane.

The distal sealing region may comprise an inferior portion having afirst wall thickness and a superior portion having a second wallthickness greater than the first wall thickness. The inferior portion ofthe distal sealing region may be configured to deflect downwards duringthe actuation phase.

The at least one movable region may comprise an inferior protrudingregion proximally adjacent an inferior portion of the distal sealingregion and protruding radially inwards towards the breast. The inferiorprotruding region may be configured to compress against a nipple or anareola of the breast during the resting phase. The inferior protrudingregion may be configured to fold downwards and away from the breastduring the actuation phase to allow breast tissue to be pulledproximally into the expandable membrane.

The at least one movable region may comprise an intermediate curvedregion distally adjacent the expandable region. The intermediate curvedregion may comprise a central portion disposed between flankingportions, wherein the central portion may have a greater thickness thanthe flanking portions. The flanking portions may be configured todeflect downwards during the actuation phase and upwards during theresting phase to cause movement of the central portion towards thebreast during the resting phase, thereby causing compression of thebreast.

The expandable membrane may further comprise a superior region disposedbetween a superior portion of the distal sealing region and theexpandable region. The superior region may comprise a distal portionhaving a first thickness and a proximal portion having a thickness thatgradually decreases from the first thickness to a thickness of theexpandable region. The distal portion of the superior region may beconfigured to compress against the breast when the at least one movableregion moves towards the breast during the resting phase. The distalportion of the superior region may comprise a textured internal surface.

The expandable region may be configured to elastically deform during theactuation phase. Alternatively or in combination, the expandable regionmay comprise one or more pleats or curved portions that allow the regionto expand radially outwards during the actuation phase. The expandableregion may not directly contact the breast during the expression ofbreast milk.

The expandable membrane may be operably coupled to the actuatableassembly via a tube coupled to the housing and to the actuatableassembly, wherein the tube and the chamber may be filled with a drivingfluid. Actuation of the actuatable assembly may cause movement of thedriving fluid into or out of the chamber. The driving fluid may comprisea substantially incompressible fluid.

The expandable membrane may be operably coupled to the actuatableassembly via a mechanical member, wherein actuation of the actuatableassembly causes the mechanical member to mechanically pull theexpandable membrane away from the breast. The mechanical member maycomprise one or more of a tensile element, an arm, or a lever coupled tothe expandable membrane.

These and other embodiments are described in further detail in thefollowing description related to the appended drawing figures.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 illustrates an exemplary embodiment of a breast milk expressionapparatus or pumping device in accordance with embodiments.

FIGS. 2A and 2B illustrate exemplary embodiments of a breast interfacesuitable for incorporation with a pumping device as disclosed herein.

FIG. 3A is a sectional view of an exemplary embodiment of a breastinterface comprising an expandable membrane having biomimetic geometry.

FIG. 3B is a 2D cross-section of the breast interface of FIG. 3B.

FIG. 4A illustrates the position of a breast at the beginning of abreast milk expression session using the breast interface of FIGS. 3Aand 3B.

FIG. 4B illustrates the interaction between the breast and the breastinterface of FIGS. 3A and 3B at maximum vacuum pressure.

FIG. 4C illustrates the interaction between the breast and the breastinterface of FIGS. 3A and 3B at minimum vacuum pressure.

DETAILED DESCRIPTION OF THE INVENTION

Specific embodiments of the disclosed devices and methods will now bedescribed with reference to the drawings. Nothing in this detaileddescription is intended to imply that any particular component, feature,or step is essential to the invention.

FIG. 1 illustrates an exemplary embodiment of a breast milk expressionapparatus or pumping device in accordance with embodiments. Pumpingdevice 100 (also known as an “expression apparatus”) includes breastinterfaces 105, a tube 110, and a controller 115 operatively coupled tobreast interfaces 105 through tube 110. Breast interfaces 105 includeresilient and conformable flanges 120, for engaging and creating a fluidseal against the breasts. Each breast interface 105 is fluidly coupledto a collection vessel 125 configured to receive the expressed breastmilk. Each breast interface 105 is additionally coupled to one or morecontrollers 115 that house the power source and drive mechanism for thepumping device 100. For example, the controller 115 may comprise anactuatable assembly for generating negative and/or positive pressure atthe breast interface to cause expression of milk from a breast fluidlysealed against the breast interface. Tube 110 may transmit suitableenergy inputs, such as mechanical energy generated by an actuatableassembly housed within the controller, from controller 115 to breastinterfaces 105. Breast interfaces 105 can then convert the energy inputsinto pressure applied against the breasts in a highly efficient manner,resulting in the expression of milk into collection vessels 125. Forexample, as described in further detail herein, the breast interface maycomprise an expandable membrane coupled to a rigid housing, wherein theexpandable member expands and contracts in response to actuation of theactuatable assembly apply pressure at the breast and thereby causeexpression of milk from the breast.

The controller 115 may further comprise hardware for various functions,such as controlling the pumping device 100, quantifying milk expression,measuring or analyzing data related to characteristics of the expressedmilk, and/or communicating with other devices. For example, thecontroller may be configured to communicate with one or more personalcomputing devices such as smartphones, tablets, or personal computers,wherein the personal computing device may be configured to provide auser interface for a user to interact with the pumping device.

The device 100 may further comprise one or more sensors configured totrack various characteristics of the collected fluid, such as thequantity of the fluid or a composition of the fluid. The one or moresensors may be coupled to one or more portions of the breast interfacesor the collection vessels, or they may be coupled to controller. Powermay be provided to the one or more sensors via a connection to thecontroller 115, or to another source of power. In embodiments in whichthe one or more sensors are coupled to one or more portions of thebreast interfaces 105 or collection vessels 125, the sensors may befurther coupled to the controller 115 via one or more communicationlines configured to transmit signals between the sensors and thecontroller.

FIGS. 2A and 2B illustrate exemplary embodiments of a breast interfacesuitable for incorporation with a pumping device as disclosed herein.FIG. 2A shows a breast interface 200 a comprising an expandable membrane205 a coupled to a rigid housing 210 to form a reservoir or chamber 215therebetween. Similarly, FIG. 2B shows a breast interface 200 bcomprising an expandable membrane 205 b coupled to a rigid housing 210to form a reservoir or chamber 215 therebetween. The expandable membrane205 a or 205 b comprises a distal opening 206 through which a nipple andthe surrounding breast tissue are received, and an expression area 209into which the nipple expresses breast milk. The expressed milk exitsthe expression area through a proximal opening (not shown) of theexpandable membrane, and enters a collection reservoir coupled to thebreast interface. The breast interface 200 a or 200 b may furthercomprise a flange 220 to receive and fluidly seal against a breast.Optionally, the expandable membrane and the flange may be formed as asingle, integrated component, having an expandable portion and a flangeportion. The expandable membrane can be configured to expand or contractin response to the actuation of an actuatable assembly operably coupledto the breast interface, thereby causing the volume of the reservoir todecrease or increase, respectively. When the expandable membraneexpands, the membrane moves away from the breast received within thebreast interface, thereby creating negative pressure at the breast. Whenthe expandable membrane contracts, the membrane moves towards thebreast, thereby increasing the pressure at the breast to return thepressure to a baseline level prior to the expansion of the expandablemembrane. The reservoir or chamber 215 can therefore provide a solesource of negative pressure for the breast interface, wherein movementof the expandable membrane 205 a or 205 b towards or away from thebreast can generate sufficient negative pressure against the breast tocause the expression of milk, without the aid of additional pressuresources such as air suction applied directly to the nipple.

The expandable membrane 205 a shown in FIG. 2A comprises a flexible orelastic material allowing the membrane to elastically deform in responseto the actuation of the pumping mechanism. For example, the expandablemembrane 205 a may comprise one or more of silicone, polyether blockamides such as PEBAX, or polychloroprenes such as neoprene, and can havea specified thickness and durometer. The expandable membrane 205 b shownin FIG. 2B comprises a membrane having one or more corrugated features225 (such as pleats) that allow expansion and contraction of themembrane. The expandable membrane 205 b may comprise an elasticallydeformable material as described in reference to expandable membrane 205a of FIG. 2A. Alternatively, the expandable membrane 205 b may befabricated from a substantially rigid material, such as stainless steel,nitinol, high durometer polymer, or high durometer elastomer. In theseembodiments, the one or more corrugated features can provide stressand/or strain distribution to enable the substantial deformation of theexpandable membrane without surpassing the yield point of the material.The amount of deformation of the expandable membrane can be controlledby many factors, (e.g., wall thickness, durometer, surface area) and canbe optimized based on the pumping device (e.g., pump power, vacuumrequirements).

In some embodiments, the expandable membrane is operably coupled withthe actuatable assembly via a fluid. For example, chamber 215 comprisesa fluid reservoir filled with a fluid, and the actuatable assembly ofthe pumping device comprises a hydraulic pumping mechanism fluidlycoupled with the reservoir. Negative pressure can be generated at thebreast interface when the fluid is displaced from reservoir by actuationof the actuatable assembly. The driving fluid may comprise any suitablefluid for transferring sufficient pressure from the actuatable assemblyto the expandable membrane to cause the expression of milk from thebreast. In many embodiments, the driving fluid may be a substantiallyincompressible fluid, such as water or oil. Suitable incompressiblefluids for hydraulic systems are known to those of skill in the art. Insome embodiments, the expandable membrane may be operably coupled withthe actuatable assembly via a mechanical member. For example, themechanical member may comprise a tensile element (e.g., cable, coil,spring, etc.), an arm, or a lever coupled to the expandable membrane,wherein actuation of the actuatable assembly causes the mechanicalmember to mechanically pull the expandable member away from the breastreceived within the breast interface, thereby generating negativepressure at the breast.

At the beginning of a breast milk expression session, wherein the nippleand surrounding breast tissue is received through the distal opening ofthe expandable membrane, the chamber or reservoir between the membraneand the housing of the breast interface may be at atmospheric pressureP_(ATM). To begin expressing milk, the actuatable assembly may beprompted to begin a pumping session, wherein the actuatable assemblyrepeatedly alternates between an actuation phase and a resting phasethroughout a pumping session. During the actuation phase, the expandablemembrane expands and moves away from the breast tissue fluidly sealedagainst the membrane, causing the pressure at the chamber to decrease toa pre-determined maximum negative pressure −P_(MAX). During the restingphase, the expandable membrane contracts and moves towards the breasttissue, causing the pressure at the chamber to increase from the maximumnegative pressure −P_(MAX) to either atmospheric pressure P_(ATM) or apre-determined minimum negative pressure −P_(MIN.) The cyclicalactuation of the actuatable assembly can thus mimic the sucking cyclesof an infant during a nursing session. During each of the actuationphase and the resting phase, the chamber may be held at the maximum andminimum vacuum pressures, respectively, for a pre-determined length oftime to model the nursing cycle of an infant.

To better simulate the mechanism of action of an infant's mouth duringnursing, the breast interface as described herein may comprise anexpandable membrane having a biomimetic geometry, specifically designedto emulate the geometry of an infant's mouth. Such a membrane may beconfigured expand and contract in response to actuation of an actuatableassembly to apply negative pressure at the breast, as described herein.In addition, the membrane may comprise various features configured tomimic the functions of various portions of the infant's mouth duringnursing.

FIGS. 3A and 3B illustrate an exemplary embodiment of a breast interface300 comprising an expandable membrane 305 having biomimetic geometry.FIG. 3A is a sectional view of the breast interface 300, and FIG. 3B isa 2D cross-section of the breast interface 300. The expandable membrane305 may be coupled to a rigid housing 310, thereby forming a chamber orreservoir 315 between the membrane and the housing. The expandablemembrane may comprise a distal opening 306 to receive the nipple and thesurrounding breast tissue, a proximal opening 308 to couple to acollection reservoir (not shown), and an expression area 309 into whichthe nipple expresses milk.

As described herein, the expandable membrane may be operably coupledwith an actuatable assembly to affect expansion and contraction of theexpandable membrane and thereby cause the expression of milk from anipple received within the expandable membrane through the distalopening. For example, the chamber 315 may be filled with a fluid, andthe housing may comprise a tubing outlet (not shown) connected to tubingalso filled with the fluid. The actuatable assembly may be operablycoupled with the tubing and configured to affect movement of the fluidwithin the tubing towards or away from the breast interface. Themovement of the fluid within the tubing can in turn cause movement ofthe fluid into or out of the chamber 315, affecting a correspondingcontraction or expansion of the expandable member to apply pressure atthe breast interface. Movement of the fluid out of the chamber, causingthe corresponding expansion of the expandable membrane and hencemovement of the membrane away from the breast captured within themembrane, can apply negative pressure at the breast, which can causemilk be expressed from the nipple. Movement of the fluid into thechamber, causing the contraction of the expandable membrane and hencemovement of the membrane toward the breast, can relieve at least aportion of the negative pressure applied at the breast due to theexpansion of the membrane. The fluid may be a substantiallyincompressible fluid such as water or oil.

The geometry of the expandable membrane 305 may be configured to mimicthe geometry of an infant's mouth. Various regions of the expandablemembrane may be configured to simulate the structure and/or function ofvarious parts of an infant's mouth. For example, as shown, theexpandable membrane may comprise one or more of a distal sealing region320, a superior region 330, an inferior protruding region 340, anintermediate curved region 350, and one or more internal expansionregions 360. The distal sealing region 320 can form a fluid seal againstthe breast received within the breast interface 300, similar in functionto the lips of an infant. The superior region 330 may simulate the hardpalate of an infant's mouth, which directs the nipple and thesurrounding breast tissue toward the throat. The inferior protrudingregion 340 may simulate the gums of an infant's mouth, and can providepinching of the captured breast tissue captured upon reduction of vacuumat the breast interface. The curved region 350 can simulate the tongueof an infant. The expansion regions 360 can simulate the throat and thesoft palate of an infant's mouth.

The expandable membrane 305 may have a varying thickness throughout theone or more various regions. When negative pressure is applied at thebreast interface, the localized thickening or thinning of each regioncan enable movement of the region similar to the movement of acorresponding region of an infant's mouth during nursing.

The distal sealing region 320, which fluidly seals against the nippleand the surrounding breast tissue, may have an inferior nominal wallthickness 322 on the inferior portion and a superior wall thickness 324on the superior portion, wherein the superior thickness 324 is greaterthan the inferior thickness 322. Therefore, the superior portion of thesealing region can be relatively rigid, while the inferior portion canbe relatively flexible. When the actuatable assembly coupled to thebreast interface is actuated and negative pressure is applied at thebreast, the thicker, more rigid superior portion can push against thetop portion of the breast, while the thinner, more flexible inferiorportion can be deflected to allow the lower portion of the breast to bepulled further inwards toward the expression area 309.

The superior region 330 may comprise a texture or ridged interiorsurface facing the breast, which can direct the nipple inwards towardsthe expression area 309 when negative pressure is applied at the breast.The distal portion 332 of the superior region can comprise a distalthickness 334 sufficient to provide structural rigidity to the region,such that the region does not deflect significantly when the nipple andthe surrounding breast tissue are compressed against the region. Whennegative pressure is applied at the breast, the nipple may be pushedupwards against the superior region via movement of the intermediatecurved region, as described herein, such that the nipple is compressedbetween the super rigid region and the intermediate curved region. Theproximal portion 336 of the superior region can comprise a graduallydecreasing thickness that tapers into the expansion region 360. Forexample, a proximal thickness 338 of the region within the proximalportion 336 may be smaller than the distal thickness 334. Thus, thesuperior region 330 gradually translates into the flexible expandableregion 360.

The expandable region 360 is disposed near the proximal opening 308 ofthe expandable membrane, and is configured to expand radially outwards,generally away from the nipple captured within the expandable membrane,when negative pressure is applied at the breast interface. For example,the reservoir 315 may be filled with a fluid, and actuation of anactuatable assembly fluidly coupled with the reservoir may causemovement of fluid out of the reservoir 315, in turn causing theexpandable region to be pulled towards the rigid housing 310. Theexpansion of the expandable region applies negative pressure at thebreast tissue that is received through the distal opening 306 andfluidly sealed against the expandable membrane. The expandable regioncan comprise a thickness 362 that allows the region to elasticallydeform in response to the pressure applied at the expandable region.Additionally, the expandable region may comprise one or more pleats orcurved portions that allow the region to expand radially outwardstowards the rigid housing. In some embodiments, the expandable regiondoes not directly contact the nipple or the surrounding breast tissue,similarly to the throat and soft palate of the infant during nursing.

The intermediate curved region 350 comprises a thicker central portion352 disposed between thinner flanking portions 354. During the pumpingcycle, the thinner flanking portions can deflect, thereby allowing thethicker central portion to move up and down towards and away from thenipple. The breast tissue can be thus compressed between the thickercentral portion of the curved region and the superior region 330. Inpreferred embodiments, the intermediate curved region is configured tocompress the breast tissue during the resting phase of the pumpingsession, or as the expandable membrane is contracting and moving backtowards the breast. During the resting phase, the chamber 315 isreturning to either atmospheric pressure or minimum vacuum pressure(e.g., during the part of the pump cycle wherein fluid volume in thereservoir 315 is increasing). The intermediate curved region can thusfunction similarly to a tongue of an infant, creating localizedcompression of the breast tissue inbetween sucking cycles. As theactuatable assembly transitions from the resting phase to the actuationphase, the thinner flanking portions can deflect to move the thickercentral portion downwards and away from the breast tissue, therebyhelping create negative pressure at the breast.

The inferior protruding region 340 may be disposed centrally over theinferior portion of the distal opening 306 into the expression area 309.The inferior protruding region can fold or unfold about an axis 342 tocreate localized compression at the breast tissue near the nipple.During the actuation phase, as pressure at the chamber 315 decreases tothe maximum negative pressure and the breast tissue is pulled furtherinto the expandable membrane towards the expression area 309, theinferior protruding region can move downwards and away from the breasttissue, “folding” about the axis 342. During the resting phase, as thepressure in the chamber increases to atmospheric or the minimum negativepressure and the breast tissue retreats or moves away from theexpression area 309, the inferior protruding region can move upwards andinto the breast tissue, “unfolding” about the axis 342. As the inferiorprotruding region moves upwards and into the breast tissue, localizedcompression is created at the breast tissue near the nipple, similarlyto the gums of an infant's mouth.

FIG. 4A illustrates the position of a breast B at the beginning of abreast milk expression session using the breast interface 300 of FIGS.3A and 3B. The breast B is received through the distal opening of theexpandable membrane 305 with the nipple N resting just past the inferiorprotruding region 340 (the “gums” element) and mid-way through thesuperior region 330. The chamber 315 is at atmospheric pressure P_(ATM).

FIG. 4B illustrates the interaction between the breast B and the breastinterface 300 at maximum vacuum pressure. As the chamber 315 reachesmaximum negative pressure −P_(MAX) via actuation of the actuatableassembly operably coupled with the expandable membrane 305, theexpandable regions 360 a and 360 b expand and move in directions 362 aand 362 b, respectively. In addition, the thinner flanking portions 354of the intermediate curved region 350 deflect downwards in the direction356, such that the thicker central portion 352 also moves downwards andaway from the nipple N. The movement of the expandable regions and theintermediate curved region towards the housing 310 and generally awayfrom the breast B creates negative pressure at the chamber 315, which istransferred to the breast via the expandable membrane. The negativepressure causes the nipple to be pulled further into the expandablemembrane in the direction 402. Accordingly, as the breast tissue ispulled further into the expandable membrane, the breast tissue applies areaction force 326 to the relatively flexible inferior portion of thedistal sealing region 320, which in turn causes the inferior portion ofthe distal sealing region to deflect and pivot slightly downwards asshown. The deflection of the inferior portion of the sealing regionallows more of the lower breast tissue to be pulled into the expandablemembrane. As the nipple N is pulled over the inferior protruding region340, the insertion force of the breast tissue causes the inferiorprotruding region to fold downwards about its axis 342 as shown, suchthat the nipple can rest over the intermediate curved region 350. Inaddition, the folding of the inferior protruding region can cause thebreast interface 300 to pivot slightly with respect to the breast in thedirection 302.

FIG. 4C illustrates the interaction between the breast B and the breastinterface 300 at minimum vacuum pressure. As described herein, as theactuatable assembly transitions from the actuation phase to the restingphase to release at least a portion of the negative pressure generatedduring the actuation phase (e.g., by returning fluid to the chamber 315,causing the expandable membrane 305 to contract), the chamber 315returns to atmospheric pressure or a pre-determined minimum negativepressure −P_(MIN). The breast interface may be held at the minimumnegative pressure −P_(MIN) for a pre-determined length of time. Asnegative pressure in the chamber 315 is at least partially released, thebreast tissue retreats in the direction 404, relieving the insertionforce exerted onto the inferior protruding region 340 during theactuation phase. Accordingly, the inferior protruding region 340 unfoldsin the direction 344 about the axis 342, digging into the breast tissueand causing localized compression on the areola and the nipple. Asdescribed herein, the thicker central portion 352 of the intermediatecurved region 350 can also move upwards during the transition from theactuation phase to the resting phase, compressing the nipple against theupper region. Compression with the inferior protruding region and/or theintermediate curved region can compress the milk ducts of the breast tocause the milk within the milk ducts to flow out through the nipple.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. An apparatus for biomimetic expression of breastmilk from a breast, the apparatus comprising: a housing; and anexpandable membrane coupled to the housing to form a chambertherebetween, the expandable membrane having a distal opening to receiveat least a portion the breast therethrough and a proximal openingopposite the distal opening, wherein the expandable membrane is operablycoupled to an actuatable assembly configured to alternate between anactuation phase and a resting phase during operation, wherein theexpandable membrane comprises an expandable region adjacent the proximalopening, the expandable region configured to expand and move towards thehousing during the actuation phase of the actuatable assembly, therebygenerating negative pressure at the breast to cause the expression ofbreast milk from the breast, and wherein the expandable membranecomprises at least one movable region disposed between the expandableregion and the distal opening, the at least one movable region includinga portion that folds against itself during biomimetic expression ofbreast milk from a breast to define an inferior protruding regiondisposed centrally over an inferior portion of the distal opening,wherein the inferior protruding region is configured to engage thebreast to simulate a gum element and provide pinching of the breast. 2.An apparatus as in claim 1, wherein a thickness of the expandablemembrane varies through different regions of the expandable membrane. 3.An apparatus as in claim 1, wherein the expandable membrane comprises adistal sealing region adjacent the distal opening, the distal sealingregion configured to fluidly seal against the breast, wherein theinferior portion has a first wall thickness and a superior portionhaving a second wall thickness greater than the first wall thickness. 4.An apparatus as in claim 3, wherein an inferior portion of the distalsealing region is configured to deflect downwards during the actuationphase.
 5. An apparatus as in claim 1, wherein the expandable membranecomprises a distal sealing region adjacent the distal opening andwherein the inferior protruding region is positioned proximally adjacentan inferior portion of the distal sealing region and protruding radiallyinwards towards the breast.
 6. An apparatus as in claim 5, wherein theinferior protruding region is configured to compress against a nipple oran areola of the breast during the resting phase.
 7. An apparatus as inclaim 5, wherein the inferior protruding region is configured to folddownwards and away from the breast during the actuation phase to allowbreast tissue to be pulled proximally into the expandable membrane. 8.An apparatus as in claim 1, wherein the at least one movable regioncomprises an intermediate curved region distally adjacent the expandableregion, the intermediate curved region comprising a central portiondisposed between flanking portions, the central portion having a greaterthickness than the flanking portions, and the flanking portionsconfigured to deflect downwards during the actuation phase and upwardsduring the resting phase to cause movement of the central portiontowards the breast during the resting phase, thereby causing compressionof the breast.
 9. An apparatus as in claim 1, wherein the expandablemembrane further comprises a superior region disposed between a superiorportion of a distal sealing region and the expandable region, thesuperior region comprising a distal portion having a first thickness anda proximal portion having a thickness that gradually decreases from thefirst thickness to a thickness of the expandable region.
 10. Anapparatus as in claim 9, wherein the distal portion of the superiorregion is configured to compress against the breast when the at leastone movable region moves towards the breast during the resting phase.11. An apparatus as in claim 10, wherein the distal portion of thesuperior region comprises a textured internal surface.
 12. An apparatusas in claim 1, wherein the expandable region is configured toelastically deform during the actuation phase.
 13. An apparatus as inclaim 1, wherein the expandable region comprises one or more pleats orcurved portions that allow the region to expand radially outwards duringthe actuation phase.
 14. An apparatus as in claim 1, wherein theexpandable region does not directly contact the breast during theexpression of breast milk.
 15. An apparatus as in claim 1, wherein theexpandable membrane is operably coupled to the actuatable assembly via atube coupled to the housing and to the actuatable assembly, wherein thetube and the chamber are filled with a driving fluid, and whereinactuation of the actuatable assembly causes movement of the drivingfluid into or out of the chamber.
 16. An apparatus as in claim 15,wherein the driving fluid comprises a substantially incompressiblefluid.